Weird screen-pixelation and crash

[Guest]

Weird periodic screen-pixelation and crash after I upgrade a friends oldish computer with new CPU, Mobo, memory, DVD-drive, and screen.

Error
http://timbrandt.dk/screen-error.jpg

New components
- BenQ 24" LCD G2450HM
- Intel Core i3-2120
- ASUS P8H61-M PRO
- Corsair XMS3 DDR3 1333MHz 2x4GB CL9
- DVD-RW drive (S-ATA)

Old components
- mATX case with PSU (300W)
- 320GB HDD (older, but I can't remember the brand, but it has S-ATA)

Notes
I sent the CPU, Mobo, and memory back to the store, and they tested it for a few days and found no errors. Sometimes it takes more than a few days for the error to appear, other times it happens several times a day. I tested with a different monitor, but that didn't change anything. I have run several stress-tests, burn-in tests, and GPU-benchmarks, and that didn't make it crash. Can it be the PSU that is the cause of it? Or is it more likely that it's the CPU or Mobo?

 

[scout_03]

it could be the psu that cannot support all the new parts do you have a pci-e graphic card you could try in the system and not using the onboard one

 

[Guest]

it could be the psu that cannot support all the new parts do you have a pci-e graphic card you could try in the system and not using the onboard one

No I actually don't have a graphics card that I can test it with. I have thought about suggesting that he get a HD5450 or something cheap, but I want to be as sure as I can before recommending any purchases

 

[scout_03]

try to borrow one from a friend that got one she does not have to be new but in good working state

 

[humphreybot]

looks to me that the resolution is set at something incompatible with the monitor or graphics card. if you concentrate you will be able to set the resolution to something basic like 800x600 and then go from there

 

[Guest]

The resolution is actually unchanged at 1920x1080, but the real problem is that it happens suddenly and from time to time, and then the computer crashes. He needs a computer that doesn't crash several times a day lol. So what's the best bet?
- Something wrong with the PSU?
- Something wrong with the CPU/Mobo?
- Something wrong with the CPU/Mobo that an external graphics-card would fix?
- Something else?

 

[scout_03]

i would try to use another psu to see if system still crash

 

[Guest]

I'll try that... thank you